As with the video about the differential I blogged about earlier, I’m not certain exactly when this documentary was produced. Based on what is shown, it would have to be between 1938 (when the AT&SF 3765 class locomotive featured in this film began its service) and 1957 (the last year of steam operation on the AT&SF). It most likely dates from the earlier part of that range.

One of the things I particularly like about this video is that it doesn’t just explain the technology, but it also shows a lot of the human activity necessary to make these wonderful machines work.